This research program is concerned with the retina and optic ganglia of arthropods as a useful experimental system in which general problems of photoreception and sensory information processing can be attacked at several levels. The techniques include: microspectrophotometry of visual pigments and their photoproducts, intra- and extra-cellular recording of receptor and synaptic potentials, and analysis of spike discharge of visual interneurons. BIBLIOGRAPHIC REFERENCES: Goldsmith, T.H. The polarization sensitivity--dichroic absorption paradox in arthropod photoreceptors. In: Photoreceptor Optics, ed. R. Menzel and A. Snyder, Springer-Verlag, pp. 382-409 (1975). Goldman, L.J., S.N. Barnes and T.H. Goldsmith. Microspectrophotometry of rhodopsin and metarhodopsin in the moth Galleria. J. Gen. Physiol. 66: 383-404 (1975).